小型家用電動絞肉機的設計

小型家用電動絞肉機的設計,小型家用電動絞肉機的設計,小型,家用,電動,絞肉機,設計 江西農(nóng)業(yè)大學畢業(yè)設計(論文)任務書 設計（論文） 課題名稱 絞肉機的設計 學生姓名 院（系） 工學院 專 業(yè) 機械設計制造及其自動化 指導教師 職 稱 講師 學 歷 畢業(yè)設計（論文）要求： 絞肉機依靠螺桿將料斗箱中的原料肉推到預切板處，通過螺桿的旋轉(zhuǎn)作用，使得絞刀與孔板產(chǎn)生相對運動，從而將原料肉切成顆粒形狀，確保了肉餡的均勻性。該機可絞切鮮肉、凍肉。用戶可根據(jù)工藝要求，選配不同規(guī)格的孔板，加工出理想的肉餡，以滿足不同肉制品的加工需要。 畢業(yè)設計（論文）內(nèi)容與技術參數(shù)： 1 摘要。簡述論文的內(nèi)容。 2 緒論。國內(nèi)外有關文獻綜述。 3 絞肉機的總體設計和運動原理。 4 總結(jié)。 畢業(yè)設計（論文）工作計劃： 1 查閱有關的國內(nèi)外文獻，并認真閱讀。 2 學習二維、三維繪圖軟件以及仿真軟件。 3 結(jié)合相關絞肉機的結(jié)構設計特點，按要求創(chuàng)新地設計一種絞肉機構。 4 按要求繪圖，打印圖紙。 5 參照論文撰寫格式撰寫論文。 接受任務日期 2008 年 11 月 6 日 要求完成日期 2009 年 5 月 10 日 學 生 簽 名 年 月 日 指導教師簽名 年 月 日 院長（主任）簽名 年 月 日 學校代碼：10410 序 號：055016 本 科 畢 業(yè) 設 計 題目： 絞肉機的設計 學 院： 姓 名： 學 號： 專 業(yè)： 機械設計制造及其自動化 年 級： 指導教師： 二 OO 九 年 五 月 絞肉機的設計 摘 要 隨著人們生活水平的提高以及對產(chǎn)品小型化，精致化，安全，便捷地需要，越來 越多的小型的家用絞肉機走進了人們的日常生活中。 本文就主要論述了家用絞肉機的工作原理、主要技術參數(shù)、傳動系統(tǒng)、典型零件 的結(jié)構設計等等。首先介紹了家用絞肉機的工作原理，即將肉放進托盤后，因為肉的 重力和推進螺桿的作用，將肉連續(xù)地送往絞刀口進行切碎。托盤面積較大，待絞肉時， 可將多余的肉放在托盤上，逐步地推進絞筒內(nèi)，減緩對刀具的壓力。同時采用彈性活 銷聯(lián)軸器聯(lián)結(jié)螺桿和電機，結(jié)構簡單，可靠性高，工作平穩(wěn)可靠，拆卸方便。推進螺 桿的螺距后大前小，根徑后小前大，使其推進螺桿與絞筒之間的容積逐漸減小，實現(xiàn) 了對物料的擠壓作用。采用可替換的絞刀和擠肉樣板，可以滿足顧客絞肥肉和瘦肉的 不同需求。 這種絞肉機結(jié)構簡單，拆洗方便，體積較小，適合普通家庭使用。 關鍵詞：家用絞肉機；推進螺桿；彈性活銷聯(lián)軸器；托盤；絞刀；擠肉樣板； 絞肉機的設計 i Abstract With the improvement of living standards as well as the miniaturization of products, refined, safe, and convenient to the needs of people，a growing number of small-scale household meat grinder is going into peoples daily life. This article focuses on the domestic meat grinder of the working principle, main technical parameters, transmission system, the structural design of typical parts and so on. First of all,it introduced the working principle of the household meat grinder,make the meat into the tray, as the meat of the gravity , the role of promoting the screw will be continuously sent to the meat cutter to shred edge. The tray is big , and the meat can be placed on the extra tray, then be gradually pushed into the cutter,so it can slow down the pressure to the tool. At the same time a flexible coupling is using to link the pin screw and motor. Its structure is simple , high reliability, stable and the disassembly is convenience. The advancing large screw pitch before the small, small front after the root diameter,and as it twist, the volume between the cage and the winch spool will be reduced gradually, then it has realized to the material suqeezing action. As the cutter knife and squeeze can be replaced, it can meet customers different needs to cut the fat and lean meat . The structure of this meat grinder is simple. It can be taken apart easyly , washed conveniently.Besides the volume is small, suits for the ordinary family use. Key words: Household meat grinder;Advancing screw; Flexible coupling live sales;Tray; Reamer;Crowded meat model 絞肉機的設計 ii 目 錄 1 緒 論 .1 1.1 引言 .1 2 絞肉機的結(jié)構及工作原理 .3 2.1 絞肉機的結(jié)構 .3 2.1.1 送料機構 .3 2.1.2 切割機構 .3 2.1.3 驅(qū)動機構 .3 2.2 絞肉機的工作原理 .4 3 螺旋供料器的設計 .5 3.1 推料螺桿的設計 .5 3.1.1 推料螺桿的材料 .5 3.1.2 螺旋直徑 .5 3.1.3 螺旋供料器的轉(zhuǎn)速 .6 3.1.4 螺旋節(jié)距 .6 3.2 絞筒的設計 .6 4 傳動系統(tǒng)的設計 .7 4.1 電機的選擇 .7 4.2 聯(lián)軸器的選擇 .8 5 絞刀設計 .9 5.1 絞刀的設計 .9 5.1.1 刀刃的起訖位置 .10 5.1.2 刀刃的前角 .11 5.1.3 刀刃的后角 .13 5.1.4 刀刃的刃傾角 .13 5.1.5 刀刃上任一點位量上絞肉速度 .15 5.1.6 刀片的結(jié)構 .16 6 軸的結(jié)構設計及校核 .18 6.1 擬定軸上零件的尺寸 .18 6.2 校核軸的強度 .20 設計總結(jié) .21 參 考 文 獻 .22 致 謝 .23 絞肉機的設計 1 緒 論 1.1 引言 隨著國民經(jīng)濟的發(fā)展和人民生活水平的提高，人民對食品工業(yè)提出了更高的要求。 現(xiàn)代食品已朝著營養(yǎng)、綠色、方便、功能食品的方向發(fā)展，且功能食品將成為新世紀 的主流食品。食品工業(yè)也成為國民經(jīng)濟的支柱產(chǎn)業(yè)，作為裝備食品工業(yè)的食品機械工 業(yè)發(fā)展尤為迅猛。 食品工業(yè)的現(xiàn)代化水平，在很大程度上依賴于食品機械的發(fā)展及其現(xiàn)代化水，離 開現(xiàn)代儀器和設備，現(xiàn)代食品工業(yè)就無從談起。食品工業(yè)的發(fā)展是設備和工藝共同發(fā) 展的結(jié)果，應使設備和工藝達到最佳配合，以設備革新和創(chuàng)新促進工藝的改進和發(fā)展， 以工藝的發(fā)展進一部促進設備的發(fā)展和完善。兩者互相促進、互相完善，是使整個食 品工業(yè)向現(xiàn)代化邁進的必要條件。 在肉類加工的過程中，切碎、斬拌攪拌工序的機械化程度最高，其中絞肉機、斬 拌機、攪拌機是最基本的加工主械.同時隨著人們對產(chǎn)品安全，便捷的要求的提高，越 來越多的小型的家用的絞肉機走進了人們的生活中。所以這種體積小，操作方便，拆 洗簡單，使用壽命長的家用絞肉機應運而生。 絞肉機是肉類工業(yè)、香腸生產(chǎn)過程中最常用的一種切割機械，它的作用是把一定尺 寸的原料肉按要求切碎成不同尺寸的顆粒狀肉，以便于同其他輔料充分混合和滿足不 同 肉制品的需要。 目前使用的絞肉機工作時主要靠旋轉(zhuǎn)的輸送絞龍將料斗中的原料肉推到絞刀箱中的 絞刀孔板處，利用轉(zhuǎn)動的切刀刃和固定的孔板孔形成的剪切作用將肉切碎并在絞龍擠 壓力的作用下將肉粒不斷的擠出孔板外，這樣來完成料斗中的肉通過絞龍進入紋刀箱 而切碎的肉粒排出機外的工作循環(huán)。整個機體為灰鑄鐵鑄造而成。該絞肉機無論從性 能結(jié)構還是制造材料都存在很多不足。 近些年來我國所生產(chǎn)的家用絞肉機一般均采用優(yōu)質(zhì)的不銹鋼制造，它的功率不大， 擠肉樣板孔徑小，擠出的肉更加細膩。這些小型機器結(jié)構簡單，部件精良，性能優(yōu)越， 選材優(yōu)質(zhì)，適合普通家庭使用。只是在長期的使用過程中卻發(fā)現(xiàn)它在結(jié)構上存在著需 要進一步改進的和完善的地方。如現(xiàn)今的絞肉機使用時都是把肉類從絞肉機的絞肉筒 進肉口塞進機內(nèi)，絞肉機一般附帶有送料棒，供用戶塞料進機身時使用，只是進料端 絞肉機的設計 1 口位于 輸送螺桿正上方，人們?nèi)菀子|及螺桿;其次，絞肉機附帶的送料棒可以輕易拔出，一些 用戶人們?yōu)樨澮粫r操作方便，而麻痹大意，直接用手把肉類塞進機內(nèi)。這就增大肢體 被螺桿卷進機內(nèi)的危機，使用戶自身置于危險當中。 絞肉機的設計 2 2 絞肉機的結(jié)構及工作原理 2.1 絞肉機的結(jié)構 絞肉機主要由送料機構、切割機構和驅(qū)動機構等組成，如圖 21 所示。 1 旋蓋 2 擠肉樣板 3 絞刀 4 推料螺桿 5 絞筒 6 托盤 7 彈性活銷聯(lián)軸器 8 電動機 9 上外殼 10 支架 11 下外殼 12 螺栓 13 螺釘 14 螺栓 15 擋板 16 氈圈 17 彈簧墊圈 圖 2-1 絞肉機結(jié)構簡圖 2.1.1 送料機構 包括托盤 6、推進螺桿 4 和絞筒 5。其作用是輸送物料前移到切割機構，并在前端 對物料進行擠壓。 2.1.2 切割機構 包括旋蓋 1,擠肉樣板 2，絞刀 3.其作用是對擠壓進人樣板孔中的物料進行切割.樣 板孔眼規(guī)格有多種，可根據(jù)不同的工藝要求隨時旋下旋蓋進行更換。 絞肉機的設計 3 2.1.3 驅(qū)動機構 包括電機 9、彈性活銷聯(lián)軸器 7。 2.2 絞肉機的工作原理 工作時，先開機后放料，由于物料本身的重力和推料螺桿的旋轉(zhuǎn)，把肉連續(xù)地送 往絞刀口進行切碎。因為推料螺桿的螺距后面應比前面小，但螺旋軸的直徑后面比前 面大，這樣對物料產(chǎn)生了一定的擠壓力，這個力迫使已切碎的肉從擠肉樣板上的孔眼 中排出。 在日常生活中，肥肉需要粗絞，而瘦肉需要細絞，以調(diào)換擠肉樣板和絞刀的方式 來達到粗絞與細絞之需。擠肉樣板有幾種不同規(guī)格的孔眼，通常粗絞用之直徑為 810 毫米、細絞用直徑 35 毫米的孔眼。粗絞與細絞的擠肉樣板，其厚度都為 1012 毫 米普通鋼板。由于粗絞孔徑較大，排料較易，故推料螺桿的轉(zhuǎn)速可比細絞時快些。因 為擠肉樣板上的孔眼總面積一定，即排料量一定，當供料螺旋轉(zhuǎn)速太快時，使物料在 切刀附近堵塞，造成負荷突然增加，對電動機有不良的影響。所以螺桿也不能轉(zhuǎn)得過 快，一般取 800016000 r/min. 絞刀刃口是順著切刀轉(zhuǎn)向安裝的。絞刀用不銹鋼制造，刀口要求鋒利，使用一個 時期后，刀口變鈍，此時應調(diào)換新刀片或重新修磨，否則將影響切割效率，甚至使有 些肉不是切碎后排出，而是由擠壓、磨碎后成漿狀排出，直接影響成品質(zhì)量，使其質(zhì) 量下降。絞刀必須與擠肉樣板貼和，不然會影響切割效率。 推料螺桿在機壁里旋轉(zhuǎn)，要防止螺旋外表與機壁相碰，若稍相碰，馬上損壞機器。 但它們的間隙又不能過大，過大會影響送料效率和擠壓力，甚至使物料從間隙處倒流， 因此這部分零部件的加工和安裝的要求較高。 絞肉機的生產(chǎn)能力不能由推料螺桿決定，而由切刀的切割能力來決定。因為切割 后物料必須從孔眼中排出，推料螺桿才能繼續(xù)送料，否則，送料再多也不行，相反會 產(chǎn)生物料堵塞現(xiàn)象。 在絞肉操作這中，不要用力將肉從投肉口往下壓，這樣不但不會使樣板的流出量 增加，而且使肉溫上升，使肉的黏著性下降。 絞肉機的設計 4 3 螺旋供料器的設計 3.1 推料螺桿的設計 推料螺桿的作用是向前輸送物料，并在前端對肉塊進行擠壓。如圖 31 所示，設 計上采用一根變螺距、變根徑的螺旋，即螺距后大前小，根徑后小前大，這樣使其推 料螺桿與絞筒之間的容積逐漸減小實現(xiàn)了對物料的擠壓作用。 推料螺桿前端方形軸處安裝絞刀，后端面上安裝一個定位鍵與彈性活銷聯(lián)軸器上 的鍵槽配合，以傳遞動力。 圖 3-1 推料螺桿 3.1.1 推料螺桿的材料 推料螺桿的材料選用不銹鋼 1Cr13. 3.1.2 螺旋直徑 查資料 【1】 得： 0.06 m 取 D60 mm5.2CGKD G生產(chǎn)能力,根據(jù)市面上使用最多，取 G0.15T/H 絞肉機的設計 5 K物料綜合特性系數(shù),查 【1】 表 1-3 得 K0.071 -物料得填充系數(shù)，查 【1】 表 13 得 0.15 物料的堆積密度 t/m ，豬肉的為 1.5t/m 3 C與螺旋供料器傾角有關的系數(shù)，查 【1】 表 14 得 C1 3.1.3 螺旋供料器的轉(zhuǎn)速 由原始數(shù)據(jù) n8000r/min 3.1.4 螺旋節(jié)距 查資料 【1】 得：帶式面型螺旋的節(jié)距 tD=60 mm 3.2 絞筒的設計 由于肉在絞筒內(nèi)受到攪動，且受擠壓力的反作用力，物料具有向后倒流的趨勢， 因此在推進螺桿的內(nèi)壁上設計了 8 個止推槽.沿圓周均勻分布，如圖 32 所示 絞筒內(nèi)壁與推進螺桿之間的間隙要適當，一般為 2-5mm。間隙太大會使物料倒流; 間隙太小推進螺桿與絞筒內(nèi)壁易碰撞。取其間隙為 4mm. 絞筒的材料可選用常做焊接件的 20 鋼。 絞肉機的設計 6 圖 3-2 絞筒 4 傳動系統(tǒng)的設計 推進螺桿的轉(zhuǎn)速不易太高，因為輸送能力并不是隨轉(zhuǎn)速增加而增加。當速度達到一 定值以后，效率反而下降，且速度過高，物料磨擦生熱，出口處的壓力升高，易引起 物料變性，影響絞肉質(zhì)量，因此推進螺桿的轉(zhuǎn)速一般在 8000 一 16000r/min 比較適宜。 本設計電機轉(zhuǎn)速選用 8000r/min。 4.1 電機的選擇 查資料 【2】 P135，得 N= =0.68(KW) 取 N=750W10Gq8.01653.2 4 G絞肉機的生產(chǎn)能力，kg/s q單位能量消耗，查 【2】 表 8-2 得 q=1.310 J/kg.4 傳動效率，一般在 0.8-0.9 之間，取 0.8 所以根據(jù) N750w，n8000r/min，查資料選用 G45212，其結(jié)構如圖 41 所示。 圖 4-1 G45212 電機結(jié)構示意圖 4.2 聯(lián)軸器的選擇 絞肉機的設計 7 已知電機功率 P=0.75KW,轉(zhuǎn)速 ，電機伸出端直徑為 19mm,推進螺桿直徑min/80rn 為 17mm,可計算得其名義轉(zhuǎn)矩 NnPT95.807.950 計算轉(zhuǎn)矩 ,查資料 【4】 表 2.5 得絞肉機的工況系數(shù) ，則TKAca 75.1aK57.189.071caT 查資料 【4】 P283，選 型彈性活銷聯(lián)軸器，它的通用性好，適用范圍廣，拆卸方便，1LF 適合于軸線對中安裝困難、盡量減少輔助工時的工況環(huán)境。 其公稱轉(zhuǎn)矩 ，許用轉(zhuǎn)速為 13640 （聯(lián)軸器材料為鋼） ；mNTn6min/r 10230 （聯(lián)軸器材料為鐵） 。軸孔直徑 d=12-19mm.i/r 絞肉機的設計 8 5 絞刀設計 絞刀的作用是切割物料。它的內(nèi)孔為半方形，安裝在推進螺桿前端的方軸上隨其 一起旋轉(zhuǎn)，刀刃的安裝方向應與推進螺桿旋向相同。絞刀的規(guī)格有 2 刃、3 刃、4 刃、 6 刃、8 刃。 由于是切割，絞刀材料需要耐腐蝕，安全可靠。絞刀用 W18Cr4V 材料制造，淬火 硬度為 HRC55 ，刃口要鋒利，與樣板配合平面應平整、光滑。 5.1 絞刀的設計 絞刀的幾何參數(shù)對所絞出肉的顆粒度以及產(chǎn)品質(zhì)量有著很大的影響，現(xiàn)對十字刀 片的各主要幾何參數(shù)進行設計。 十字刀片如圖(51)所示。其每一刃部的絞肉(指切割肉的)線速度 分布亦如該圖 所示。從圖上可以看出其刃部任一點位置上只有法向速度 。 v 圖 5-1 絞肉機絞刀片示意圖及每一葉刀片上速度分布 其值為： （ ）30nvp Rr 式中： 刀片刃部任一點的線速度 ms； n刀片的旋轉(zhuǎn)速度 rpm； 刀片刃部任一點至旋轉(zhuǎn)中心的距離 mm； 絞肉機的設計 9 r刀刃起始點半徑 mm ； R刀刃終止點半徑 mm； 再從任一葉刀片的橫截面上來看 圖(5-1)AA 截面，其刃部后角 較大，而前 角 及刃傾角 都為零。 因此，該刀片的幾何參數(shù)(角度)不盡合理。故再將以一葉刀片的與網(wǎng)眼扳相接觸 的一條刀刃為對象，分析刀片上各參數(shù)的作用及其影響，設計各參數(shù)。 5.1.1 刀刃的起訖位置 絞肉時，絞肉機的十字刀片作旋轉(zhuǎn)運動。從式I可以看出，在轉(zhuǎn)速一定的條件下， 刀刃離旋轉(zhuǎn)中心點越遠，則絞肉(指切割肉的)線速度越快。并且在螺桿進科速度也一 定的條件下，假定絞肉時刀片所消耗的功全部轉(zhuǎn)化為熱能，則任一與網(wǎng)眼板相接觸的 刀刃，在單位時間內(nèi)產(chǎn)生的熱量為： VFQ 式中：Q單位時間內(nèi)任一與網(wǎng)眼板相接觸的刀刃切割肉所產(chǎn)生的熱量（Js） F鉸肉時任一與網(wǎng)眼板相接觸的刀刃上的切割力（N）（參見第二部分刀刃的 前角式4) 任一刀刃切割肉的線速度（ms） 所以，絞肉(切割肉)的線速度越快，則所產(chǎn)生的熱量也越大，因此絞肉的線速度 不能很高。 根據(jù)經(jīng)驗，我們知道一般絞肉時刀刃切割肉的錢速度處在 440 一 1760mmin 之間最為理想，因此由這些數(shù)據(jù)可估算出刀刃的起訖位置，即刃的起點半 徑 和終點半徑 R。 根據(jù)式1得： 3n 30 我們已知十字刀片得轉(zhuǎn)速n10000r/min 當 時， ，mi 440m/min=7.3m/sr m73.10/ 絞肉機的設計 10 當 時， ， minR sm/3.29in/1760 R 8.3/ 圓整后取:r=7mm R=28mm 5.1.2刀刃的前角 當十字刀片絞肉時，其任一與網(wǎng)限板相接觸的刀刃上的受力情況如圖(5-2)所示。 圖5-2 與網(wǎng)眼板相接觸的刀刃的受力分析 根據(jù)圖5-2可知： fnfnFF 其值為： sincoisfnfnfn FF 因為刀刃與網(wǎng)眼板的摩擦力為： nf 肉與前刀面的摩擦力為： 絞肉機的設計 11 nFf 整理得： 4 cos)1()(2nnF 式中：F鉸肉時任一與網(wǎng)眼板相接觸的刀刃上的切割力（N） 刀片絞肉時肉的剪切抗力（N） 刀刃與網(wǎng)眼板的摩擦系數(shù) 肉被剪切時與前刀面的摩擦系數(shù) 刀片的前角（ ）90 網(wǎng)眼板作用于刀刃上的壓力（N）nF 肉被切割時作用于前刀面的壓力（N） 由于 A 式中： 肉的抗剪應力，與肉的質(zhì)地有關. 肉被剪切的面積，與網(wǎng)眼板的網(wǎng)眼直徑有關 所以 與肉的質(zhì)地及網(wǎng)眼的直徑有關，故選定網(wǎng)眼板之后， 可以看成為常量，故F F 令 。1C 由于 是網(wǎng)眼板作用于刀刃上的壓力，可以看為刀片的預緊壓力，是常量，故令n 。 是刀片切割肉時，肉對前刀面的壓力與速度v有關，故令 。2Fn vnF 簡化式4得： 5cos)1()(221 vFC 從式5和式2可知，刀刃前角 的大小，直接影響著絞肉過程中的切割力，以 及切割肉時所產(chǎn)生的溫度。 在刀片旋轉(zhuǎn)速度以及螺桿進料速度都一定的情況下，前角大，切割肉所需的力和 切割肉所產(chǎn)生的熱都??；反之，則大。但前角很大時，則因刀具散熱體積小而使切割 肉時所產(chǎn)生的溫度不能很快冷卻。因此，在一定的條件下，前角有一合理的數(shù)值范圍： 絞肉機的設計 12 一般?。?(肉質(zhì)軟取大值，反之取小值)4025 5.1.3刀刃的后角 刀刃后角的目的：一是減小后刀面與網(wǎng)眼板(包括三眼板)表面的摩擦；二是在前 角不變的情況下，增大后角能使刀刃鋒利。 刀片磨損后將使刀刃變鈍，使肉在絞肉(切割)過程中變形能增加，同時由于磨損 后刀片的后角基本為零，加大了刀片與網(wǎng)眼扳的摩擦，兩者都使絞肉過程中產(chǎn)生的熱 量增多。 另外，在同樣的磨鈍標準V B下，后角大的刀片由新用到鈍所磨去的金屬體積較大 如圖5-3所示。這說明增大后角可提高刀片的耐用度，但同時也帶來的問題是刀片的 N B磨損值大 (反映在刀體材料的磨損過大這一方面 )，并且刀刃極度也有所削弱，故后 角也有一合理的數(shù)值范圍： 一般取： (肉質(zhì)軟取大值反之取小值)53 圖5-3 后角與VB、NB的關系 5.1.4 刀刃的刃傾角 從分析由前刀面和后刀面所形成的刀刃來得知刀傾角 對刀片性能的影響情況。 在任一葉刀片的法剖面內(nèi)，當把刀刃放大看時，可以把刀刃看成是一段半徑為 的圓，由于刀刃有刃傾角 ，故在線速度方向剖面內(nèi)的刀刃將變成橢圓弧(斜剖刀刃r 圓柱所得) 絞肉機的設計 13 橢圓的長半徑處的曲率半徑，即為刀刃實際純圓半徑 。 er0 其關系為： 6 cos0ner 由此可見，增大刀傾角 的絕對值，可減小刀刃的實際鈍圓半徑 ，這就說明增er0 大刃傾角就可使刀刃變得較為鋒利。 一旦刀刃的起訖半徑 r 及 R 確定后，其最大初始刃傾角 就可確定了參見圖max0 5-5： 圖 5-5 最大初始刃傾角示意圖 = 7Rr/acsinmx016 初始刃傾角按下式計算： 見圖 5-6 絞肉機的設計 14 圖 5-6 初始刃傾角計算用示意圖 815)/(20 bRractg 式中：r刀刃起始點半徑(mm)； R刀刃終止點半徑(mm)； b葉刀片外端寬度（mm），取 ;mb4 初始刃傾角；0 5.1.5 刀刃上任一點位量上絞肉速度 由于有了刃傾角，故刀刃上任一點相對于網(wǎng)眼板的速度 ，將可以分解為垂直于v 刃的法向速度分量 和平行于刃的切向速度 分量 。參見圖 5-7nv r 即： 其值為： )(30Rrnvcosnivr 絞肉機的設計 15 圖 57 刀刃上任一點的速度示意圖 又因為： /sin R 所以： 30sincos 22 整理得 0/sin22Rvn （ ）30/sinRvRpr 式中： 刀刃上任一點位置的法向速度分度 ms；nv 刀刃上任一點位置的切向速度分量 ms； 刀刃上任一點至刀片旋轉(zhuǎn)中心距離 mm； 刀刃的初始刃傾角； 與刀刃相切的圓計算半徑 mm； R刀刃的終點半徑 mm； r刀刃的起點半徑 mm； 5.1.6 刀片的結(jié)構 絞肉機的設計 16 根據(jù)以上對絞刀各個幾何參數(shù)的分析，得出絞刀的結(jié)構圖（圖 5-8），此絞刀的特 點： 1、 后角取 4 ，刀片的壽命較長； 2、 前角取 30 ，以減小絞肉所需的力及功率； 3、 增加刃傾角，以提高刀刃的鋒利度； 4、 采用全圓弧形的前刀面結(jié)構，以改善刀刃的強度 5、 采用可換式刀片結(jié)構，以節(jié)約刀體材料并可選用不同幾何參數(shù)刀片。 絞肉機的設計 17 圖 5-8 絞刀的結(jié)構圖 6 軸的結(jié)構設計及校核 6.1 擬定軸上零件的尺寸 圖 6-1 軸的結(jié)構 1、根據(jù)軸向定位要求確定軸徑與長度 1）為滿足聯(lián)軸器的軸向定位要求，1-1 端需制出一軸肩，取 1 段軸徑為 21mm,伸出 段軸徑為 17 mm，半聯(lián)軸器與軸配合的轂孔長度為 26 mm. 2）1-2 端螺桿直徑前面已確定，為 30mm，為增加擠壓力，將螺桿軸制有一定錐度， 取 1-1 端軸徑為 26mm. 3）根據(jù)刀具孔為半方型，高度為 8mm，厚度為 4mm，為防止刀具軸向滑動，取 3-4 絞肉機的設計 18 段軸寬為 8mm，長為 5mm. 4)為防止軸徑變化太大，使刀具軸被折斷，取 2-3 段為過渡軸，軸徑為 20mm. 5）為防止刀具與擠肉樣板發(fā)生碰撞，在 4-4 左端安放了 2 個標準型 GB93-87 型彈 簧墊圈，從而使軸承與軸貼合。 2、軸上零件的周向定位 半聯(lián)軸器與軸的周向定位采用平鍵連接。查資料 【6】 P140 表 14-1 查得平鍵截面 ，鍵槽用鍵槽銑刀加工，長為 18mm（標準鍵長，見)79106(5GBhb GB1096-79）,同時為了保證聯(lián)軸器與軸有良好的對中性，選其配合為 H7/s6. 3、確定軸上倒角尺寸 參考資料 【6】 表 11-5 取 1-1 右端倒角為 ，4-4 左端倒角為 。45145.0 4、求軸上的載荷 根據(jù)軸的結(jié)構做出軸的受力簡圖。 圖 3.3 因為整個軸所受彎矩較小，故可按軸的扭矩進行計算。 根據(jù)軸的生產(chǎn)能力為 150kg/h,估算出絞刀所受的力為 30N。根據(jù)絞刀的絞刃半 徑 r R,取中點 =10.5，其扭矩為 .估算聯(lián)軸器端扭 NT5.30.11m 矩 T= 。畫出其扭矩圖，如圖 3.4.mN89075.10953 絞肉機的設計 19 圖 3.4 6.2 校核軸的強度 根據(jù)軸的受力和扭矩圖，我們可以看出 1-1 端處截面所受的計算扭矩最大，屬 于危險截面。主要對此處進行校核。 查資料 【3】 表 11-5 可得此處的抗扭截面模量 =dtbWT2)(16 3 =887.4172)5.(.5167 233m 軸的扭轉(zhuǎn)切應力 =1.003Mpa4.8790TW 查資料 【3】 表 11-3 得軸的許用扭轉(zhuǎn)切應力 =40-50T 所以 ,安全。T 絞肉機的設計 20 設計總結(jié) 漫長而又倍感充實的畢業(yè)設計階段即將結(jié)束，通過這幾個月的學習，我覺得自己的 專業(yè)知識和獨立思考問題的能力有了很大的提高，對我走向社會從事專業(yè)工作有著深 遠的影響?，F(xiàn)在談談對本次畢業(yè)設計的認識和體會。 首先，我感觸最深的就是：實踐的重要性。這次設計中我做了許多重復性的工作， 耽誤了很多的時間，但是這些重復性的工作卻增強了我的實踐能力和動手能力，積累 了設計經(jīng)驗。同時也得到一條經(jīng)驗，搞設計不能只在腦子里想它的結(jié)構，必須動手， 即使你想的很完美，但是到實際的設計過程時，會遇到許多意不到的問題。 其次，我學會了查閱資料和獨立思考。當開始拿到畢業(yè)設計題目時，心里真的是 一點頭緒也沒有，根本不知道從那里下手。在肖老師的指導下，我開始查閱相關書籍， 借鑒他人的經(jīng)驗，結(jié)合自己的構想，再利用自己所學過的專業(yè)知識技能， ，深入了解了 機械傳動原理及機械系統(tǒng)的設計方案，把設計意圖從構想階段變?yōu)榭勺x者付諸生產(chǎn)的 實現(xiàn)階段。所以我要衷心地感謝肖老師，因為她不僅非常耐心，而且還教給我了嚴謹， 認真的工作態(tài)度。另外，我發(fā)現(xiàn)每一個設計都是一個創(chuàng)新、修改、完善的過程，在設 計的過程中，運用自己所掌握的知識，發(fā)揮自己的想象力來搞好自己的設計，這個過 程也是一個學習的過程。這是一個艱辛的過程，很幸運能在肖麗萍老師的指導下，邊 學邊用，才能按時按量完成規(guī)定的任務。 設計的完成，給了我很大的信心：我完全有能力利用自己所學過的知識和技能完 成我并不熟悉的任務。在設計過程我更深切的體會到：獨立自主是關鍵，相互協(xié)作更 絞肉機的設計 21 重要。 參 考 文 獻 1 張裕中主編.食品加工技術裝備.北京:中國輕工業(yè)出版社,2007 2 張坤生主編, 肉制品加工原理與技術.北京：中國輕工業(yè)出版社， 2005 3 楊明忠，朱家誠編，機械設計.武漢：武漢理工大學出版社，2001 4 周眀衡主編，聯(lián)軸器選用手冊。北京：化學工業(yè)出版社，2000 5 孫寶鈞主編，機械設計基礎。北京：機械工業(yè)出版社，2005 6 王昆，何小柏，汪信遠主編， 機 械 設 計 機械設計基礎 課程設計。北京：高等教育 出版社，1996 7 曾正明主編, 機械工程材料手冊.北京：機械工業(yè)出版社， 2003 8 周元康,林昌華,張海兵編，機械設計課程設計.重慶：重慶大學出版社,2001 9 趙清，張玉茹編，小型電動機。北京：電子工業(yè)出版社，2003 10 李滿林編，肉類加工機械。北京：化學工業(yè)出版社，2006 11 任發(fā)政編，肉制品加工技術。北京：化學工業(yè)出版社，1999 絞肉機的設計 22 致 謝 這次畢業(yè)設計可以圓滿地完成，除了我自己查找了大量的資料，做了大量的工作 以外，還要感謝各位同學跟老師的幫助。 首先要感謝一下我的同學，雖然是我一個人做設計，但是每當我遇到什么問題去 跟他們討論，不管他們在不在忙都會很熱心地告訴我，這讓我非常感動。 另外我要感謝幫助過我的老師，特別是我的指導老師肖麗萍老師，每次我有什么 問題，不管是不是放假休息，她都會盡量抽出時間幫我，給我提出設計里存在的問題， 讓我有一個非常清晰的思路來完成設計。另外她嚴謹?shù)墓ぷ鲬B(tài)度也讓我受益匪淺。 總的來說，如果沒有他們的幫助，這次的設計我不會完成地這么順利，所以在此 我要向他們表示衷心地感謝！ 編 號 20055016 江西農(nóng)業(yè)大學 工學院 畢業(yè)設計材料 題 目 絞肉機的設計 專 業(yè) 機械設計制造及其自動化 學生姓名 材 料 目 錄 序號 附 件 名 稱 數(shù)量 備注 1 畢業(yè)設計論文 1 2 二〇〇九年五月 Int J Adv Manuf Technol (2005) 25: 551–559 DOI 10.1007/s00170-003-1843-3 ORIGINAL ARTICLE S.H. Masood · B. Abbas · E. Shayan · A. Kara An investigation into design and manufacturing of mechanical conveyors systems for food processing Received: 29 March 2003 / Accepted: 21 June 2003 / Published online: 23 June 2004 ? Springer-Verlag London Limited 2004 Abstract This paper presents the results of a research investi- gation undertaken to develop methodologies and techniques that will reduce the cost and time of the design, manufacturing and assembly of mechanical conveyor systems used in the food and beverage industry. The improved methodology for design and production of conveyor components is based on the minimisa- tion of materials, parts and costs, using the rules of design for manufacture and design for assembly. Results obtained on a test conveyor system verify the bene?ts of using the improved tech- niques. The overall material cost was reduced by 19% and the overall assembly cost was reduced by 20% compared to conven- tional methods. Keywords Assembly · Cost reduction · Design · DFA · DFM · Mechanical conveyor 1 Introduction Conveyor systems used in the food and beverage industry are highly automated custom made structures consisting of a large number of parts and designed to carry products such as food cartons, drink bottles and cans in fast production and assembly lines. Most of the processing and packaging of food and drink in- volve continuous operations where cartons, bottles or cans are re- quired to move at a controlled speed for ?lling or assembly oper- ations. Their operations require highly ef?cient and reliable me- chanical conveyors, which range from overhead types to ?oor- mounted types of chain, roller or belt driven conveyor systems. In recent years, immense pressure from clients for low cost but ef?cient mechanical conveyor systems has pushed con- veyor manufacturers to review their current design and assembly methods and look at an alternative means to manufacture more economical and reliable conveyors for their clients. At present, S.H. Masood (u) · B. Abbas · E. Shayan · A. Kara Industrial Research Institute Swinburne, Swinburne University of Technology, Hawthorn, Melbourne 3122, Australia E-mail: smasood@swin.edu.au  most material handling devices, both hardware and software, are highly specialised, in?exible and costly to con?gure, install and maintain [1]. Conveyors are ?xed in terms of their locations and the conveyor belts according to their synchronised speeds, mak- ing any changeover of the conveyor system very dif?cult and ex- pensive. In today’s radically changing industrial markets, there is a need to implement a new manufacturing strategy, a new system operational concept and a new system control software and hard- ware development concept, that can be applied to the design of a new generation of open, ?exible material handling systems [2]. Ho and Ranky [3] proposed a new modular and recon?gurable 2D and 3D conveyor system, which encompasses an open re- con?gurable software architecture based on the CIM-OSA (open system architecture) model. It is noted that the research in the area of improvement of conveyor systems used in beverage in- dustry is very limited. Most of the published research is directed towards improving the operations of conveyor systems and inte- gration of system to highly sophisticated software and hardware. This paper presents a research investigation aimed at im- proving the current techniques and practices used in the de- sign, manufacturing and assembly of ?oor mounted type chain driven mechanical conveyors in order to reduce the manufactur- ing lead time and cost for such conveyors. Applying the con- cept of concurrent engineering and the principles of design for manufacturing and design for assembly [4, 5], several critical conveyor parts were investigated for their functionality, material suitability, strength criterion, cost and ease of assembly in the overall conveyor system. The critical parts were modi?ed and redesigned with new shape and geometry, and some with new materials. The improved design methods and the functionality of new conveyor parts were veri?ed and tested on a new test con- veyor system designed, manufactured and assembled using the new improved parts. 2 Design for manufacturing and assembly (DFMA) In recent years, research in the area of design for manufacturing and assembly has become very useful for industries that are con- 552 sidering improving their facilities and manufacturing methodol- ogy. However, there has not been enough work done in the area of design for conveyor components, especially related to the is- sue of increasing numbers of drawing data and re-engineering of the process of conveyor design based on traditional methods. · · · · ·  Emphasise standardisation Use the simplest possible operations Use operations of known capability Minimise setups and interventions Undertake engineering changes in batches A vast amount of papers have been published that have investi- gated issues related to DFMA and applied to various methodolo- gies to achieve results that proved economical, ef?cient and cost effective for the companies under investigation. The main classi?cations of DFMA knowledge can be iden- ti?ed as (1) General guidelines, (2) Company-speci?c best prac- tice or (3) Process and or resource-speci?c constraints. General guidelines refer to generally applicable rules-of-thumb, relat- ing to a manufacturing domain of which the designer should be aware. The following list has been compiled for DFM guidelines [6]. These design guidelines should be thought of as “optimal suggestions”. They typically will result in a high-quality, low- cost, and manufacturable design. Occasionally compromises must be made, of course. In these cases, if a guideline goes against a marketing or performance requirement, the next best alternative should be selected [7]. Company-speci?c best practice refers to the in-house design rules a company develops, usually over a long period of time, and which the designer is expected to adhere to. These design rules are identi?ed by the company as contributing to improved quality and ef?ciency by recognising the overall relationships between · · · · · · · · · · · · · · · · ·  Design for a minimum number of parts Develop a modular design Minimise part variations Design parts to be multifunctional Design parts for multiuse Design parts for ease of fabrication Avoid separate fasteners Maximise compliance: design for ease of assembly Minimise handling: design for handling presentation Evaluate assembly methods Eliminate adjustments Avoid ?exible components: they are dif?cult to handle Use parts of known capability Allow for maximum intolerance of parts Use known and proven vendors and suppliers Use parts at derated values with no marginal overstress Minimise subassemblies particular processes and design decisions. Companies use such guidelines as part of the training given to designers of products requiring signi?cant amounts of manual assembly or mainte- nance. Note that most of the methodologies are good at either being quick and easy to start or being more formal and quanti- tative. For example, guidelines by Boothroyd and Dewhurst [8] on DFA are considered as being quantitative and systematic. Whereas the DFM guidelines, which are merely rules of thumb derived from experienced professionals, are more qualitative and less formal [9]. 3 Conventional conveyor system design Design and manufacturing of conveyor systems is a very com- plex and time-consuming process. As every conveyor system is a custom-made product, each project varies from every other project in terms of size, product and layout. The system design Fig. 1. Layout of conveyor sys- tem for labelling plasic bottles 553 is based on client requirements and product speci?cations. More- over, the system layout has to ?t in the space provided by the company. The process of designing a layout for a conveyor sys- tem involve revisions and could take from days to months or in some instances years. One with the minimum cost and maximum client suitability is most likely to get approval. Figure 1 shows a schematic layout of a typical conveyor system installed in a production line used for labelling of plastic bottles. Different sections of the conveyor system are identi?ed by speci?c technical names, which are commonly used in similar industrial application. The “singlizer” sec- tion enables the product to form into one lane from multiple lanes. The “slowdown table” reduces the speed of product once it exits from ?ller, labeller, etc. The “mass ?ow” sec- tion is used to keep up with high-speed process, e.g., ?ller, labeller, etc. The “transfer table” transfers the direction of prod- uct ?ow. The purpose of these different conveyor sections is thus to control the product ?ow through different processing machines. A typical mechanical conveyor system used in food and bev- erage applications consists of over two hundred mechanical and electrical parts depending on the size of the system. Some of the common but essential components that could be standard- ised and accumulated into families of the conveyor system are side frames, spacer bars, end plates, cover plates, inside bend plates, outside bend plates, bend tracks and shafts (drive, tail and slave). The size and quantity of these parts vary according to the length of conveyor sections and number of tracks correspond- ing to the width and types of chains required. The problems and shortcomings in the current design, manufacturing and assembly of mechanical conveyors are varied, but include:  4 Areas of improvement In order to identify the areas of cost reduction in material and labour, a cost analysis of all main conveyor parts was conducted to estimate the percentage of cost of each part in relation to the total cost of all such parts. The purpose of this analysis was to identify the critical parts, which are mainly responsible for in- creasing the cost of the conveyor and thereby investigate means for reducing the cost of such parts. Table 1 shows the cost analysis of a 50-section conveyor sys- tem. The analysis reveals that 12 out of 15 parts constitute 79% of the total material cost of the conveyor system, where further improvements in design to reduce the cost is possible. Out of these, seven parts were identi?ed as critical parts (shown by an asterisk in Table 1) constituting maximum number of compo- nents in quantity and comprising over 71% of overall material cost. Among these, three components (leg set, side frame and support channel) were found to account for 50% of the total conveyor material cost. A detailed analysis of each of these 12 parts was carried out considering the principles of concurrent en- gineering, design for manufacture and design for assembly, and a new improved design was developed for each case [10]. De- tails of design improvement of some selected major component are presented below. 5 Redesign of leg set assembly In a conveyor system, the legs are mounted on the side frame to keep the entire conveyor system off the ?oor. The existing design of conveyor legs work, but they are costly to manufacture, they · · · · Over design of some parts High cost of some components Long hours involved in assembly/maintenance Use of non-standard parts have stability problems, and cause delays in deliveries. The delay is usually caused by some of the parts not arriving from over- seas suppliers on time. The most critical speci?cations required for the conveyor legs are: Table 1. Conveyor critical parts based on parts cost analysis Product description Leg set? Side frame? Support channel? Bend tracks Rt. roller shaft? Tail shaft Spacer bar? Support wear strip? Support side wear strip? End plate Cover plate Bend plates Torque arm bracket Slot cover Inside bend plate  Qty 68 80 400 8 139 39 135 400 132 39 39 8 18 97 8  Material used Plastic leg + SS tube 2.5 mm SS C channel SS Plastic 20 dia. SS shaft 35 dia. Stainless steel 50X50X6 SS 40 × 10 mm plastic Plastic 2.5 mm/SS 1.6 mm S/S 2.5 mm/SS 6 mm S/S plate Stainless steel 2.5 mm/SS  Cost (%) 20.22 16.07 15.00 14.36 6.70 6.27 5.43 5.36 3.01 1.88 1.57 1.29 1.21 0.97 0.66  Improvement possible (Yes/No) Yes Yes Yes No Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Total ?Critical  parts 100.00 554 · · · ·  Strength to carry conveyor load Stability Ease of assembly Ease of ?exibility (for adjusting height)  1 and part 3 in Fig. 2) was not rigid enough. The connections for these parts are only a single 6 mm bolt. At times, when the conveyor system was carrying full product loads, it was observed that the conveyor legs were unstable and caused mechanical vi- bration. One of the main reasons for this was due to a single bolt Figure 2 indicates all the parts for the existing design of the conveyor leg. The indicated numbers are the part numbers described in Table 2, which also shows a breakdown of cost an- alysis complete with the labour time required to assemble a com- plete set of legs. The existing leg setup consists of plastic leg brackets ordered from overseas, stainless steel leg tubes, which are cut into speci?ed sizes, leg tube plastic adjustments, which are clipped onto the leg tube at the bottom as shown in Fig. 2. Lugs, which are cut in square sizes, drilled and welded to the leg tube to bolt the angle cross bracing and backing plate to support leg brackets bolts. The # of parts in Table 2 signi?es the number of components in each part number and the quantity is the con- sumption of each part in the leg design. Companies have used this design for many years but one of the common complaints reported by the clients was of the instability of legs. From an initial investigation, it became clear that the connec- tion between the stainless steel tube and plastic legs bracket (part Fig. 2. Existing leg design assembly with part names shown in Table 1 Table 2. Cost analysis for old leg design assembly connection at each end of the lugs in part 3 and part 7. The sta- bility of the conveyor is considered critical matter and requires recti?cation immediately to satisfy customer expectations. Considering the problems of the existing conveyor leg de- sign and the client’s preferences, a new design for the conveyor leg was developed. Generally the stability and the strength of the legs were considered as the primary criteria for improve- ment in the new design proposal but other considerations were the simplicity of design, minimisation of overseas parts and ease of assembly at the point of commissioning. Figure 3 shows, the new design of the conveyor’s leg assembly, and Table 3 gives a description and the cost of each part. Figure 3 shows that the new design consists of only ?ve main parts for the conveyor’s leg compared to eight main parts in the old design. In the old design, the plastic leg bracket, the leg tube plastic adjustment and the leg tube were the most expensive items accounting for 72% of the cost of leg assembly. In the new Part no. 1 5, 6 4 7 2 3 8  Part description Plastic leg bracket Leg tube plastic adjustment Lug Angle cross bracing Backing plate Leg tube Bolts  # of parts 2 4 2 1 2 2 6  Qty 2 2 2 1 2 2 6  Cost $ 30.00 $ 28.00 $ 4.00 $ 5.00 $ 4.00 $ 25.00 $ 3.00  Source Overseas Overseas In-house In-house In-house In-house In-house Total assembly cost (welding) $ 15.00 In-house Total 19 17 $ 114.00 555 Fig. 3. New design for leg assembly with part names in Table 3 Table 3. Cost analysis for new design leg assembly Part no. 1 3 4 5 2  Part description Stainless steel angle (50 × 50 × 3 mm) Leg plastic adjustment Cross brassing Bolts Backing plate  # of parts 2 2 1 8 2  Qty 2 2 1 4 2  Cost $ 24.00 $ 10.00 $ 7.00 $ 4.00 $ 4.00  Source In-house Overseas In-house In-house In-house Total assembly cost $ 10.00 In-house Total design, those parts have been replaced by a stainless steel angle and a new plastic leg adjustment reducing the cost of leg assem- bly by almost 50%. Thus the total numbers of parts in the leg have been reduced from 19 to 15 and the total cost per leg setup 15 · · · · 11 Size of side frame (depth) Strength of the material Ease for assembly Ease for manufacturing $ 59.00 has been reduced by $ 55 in the new design. The new conveyor leg design, when tested, was found to be more secure and stable than the old design. The elimination of part number 1 and 5 from old conveyor design has made the new design more stable and rigid. In addition, the width of the cross bracing has also been increased with two bolts mount instead of one in old design. This has provided the entire conveyor leg setup an additional strength. 6 Redesign of the side frames The side frame is the primary support of a conveyor system that provides physical strength to conveyors and almost all the parts are mounted on it. The side frame is also expected to have a rigid strength to provide support to all the loads carried on the conveyor. It also accommodates all the associated conveyor components for the assembly. The critical considerations of side frame design are: Figure 4 shows the side frame dimension and parameters. The side frame used in existing design appears to be of rea- sonable depth in size (dimension H in Fig. 4). From the initial investigation, it was found that the distance between spacer bar holes and return shaft (dimensions G and F in Fig. 4) could be reduced, as there was some unnecessary gap between those two components. The important point to check before rede?ning the design parameters was to make sure that after bringing those two closer, the return chains would not catch the spacer bar while the conveyor is running. The model of the new side frame design was drawn on CAD to ensure all the speci?cations are sound and the parts are placed in the position to check the clearances and the ?ts. Using the principle of design for manufacturing the new side frame design was made symmetrical so that it applies to all types of side frames. This change is expected to reduce the size of side frame signi?cantly for all sizes of chains. Table 4 shows a comparison of dimensions in the old design and the new design of side frames for the same chain type. It 556 Fig. 4. Side frame dimensions Table 4. New and old side frame dimension parameters Old design Chain type 3.25 LF/SS  STR/LBP/MAG A 31 B 92 C 71 D 196 E 65 F 105 G 211 H 241 I 136 J 58 K 85 L 196 TAB 22 83 62 187 56 96 202 232 127 New design Chain type 3.25 LF/SS  STR/LBP/MAG/TAB A 31 B 100 C 73 D 173 E 67 F 107 G 167 H 199 I 92 J 58 K 85 L 152 is noted that the overall size (depth) of the conveyor has been reduced from 241 mm to 199 mm (dimension H), which gives a saving of 42 mm of stainless steel on every side frame manu- factured. Thus, from a stainless steel sheet 1500 × 3000 mm, the old design parameter